#include "bn.h"

#ifndef WITH_LIBCRYPTO
//FIXME Not checked on threadsafety yet; after checking please remove this line
/* crypto/bn/bn_word.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The license and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution license
 * [including the GNU Public License.]
 */

#include <stdio.h>
#include "bn_lcl.h"
#include "openssl_mods.h"

BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
{
#ifndef BN_LLONG
	BN_ULONG ret = 0;
#else
	BN_ULLONG ret = 0;
#endif
	int i;

	w &= BN_MASK2;
	for(i = a->top - 1; i >= 0; i--)
	{
#ifndef BN_LLONG
		ret = ((ret << BN_BITS4) | ((a->d[i] >> BN_BITS4)&BN_MASK2l)) % w;
		ret = ((ret << BN_BITS4) | (a->d[i] & BN_MASK2l)) % w;
#else
		ret = (BN_ULLONG)(((ret << (BN_ULLONG)BN_BITS2) | a->d[i]) %
						  (BN_ULLONG)w);
#endif
	}
	return ((BN_ULONG)ret);
}

BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
{
	BN_ULONG ret;
	int i;

	if(a->top == 0) { return (0); }
	ret = 0;
	w &= BN_MASK2;
	for(i = a->top - 1; i >= 0; i--)
	{
		BN_ULONG l, d;

		l = a->d[i];
		d = bn_div_words(ret, l, w);
		ret = (l - ((d * w)&BN_MASK2))&BN_MASK2;
		a->d[i] = d;
	}
	if((a->top > 0) && (a->d[a->top - 1] == 0))
		{ a->top--; }
	return (ret);
}

int BN_add_word(BIGNUM *a, BN_ULONG w)
{
	BN_ULONG l;
	int i;

	if(a->neg)
	{
		a->neg = 0;
		i = BN_sub_word(a, w);
		if(!BN_is_zero(a))
			{ a->neg = !(a->neg); }
		return (i);
	}
	w &= BN_MASK2;
	if(bn_wexpand(a, a->top + 1) == NULL) { return (0); }
	i = 0;
	for(;;)
	{
		l = (a->d[i] + (BN_ULONG)w)&BN_MASK2;
		a->d[i] = l;
		if(w > l)
			{ w = 1; }
		else
			{ break; }
		i++;
	}
	if(i >= a->top)
		{ a->top++; }
	return (1);
}

int BN_sub_word(BIGNUM *a, BN_ULONG w)
{
	int i;

	if(BN_is_zero(a) || a->neg)
	{
		a->neg = 0;
		i = BN_add_word(a, w);
		a->neg = 1;
		return (i);
	}

	w &= BN_MASK2;
	if((a->top == 1) && (a->d[0] < w))
	{
		a->d[0] = w - a->d[0];
		a->neg = 1;
		return (1);
	}
	i = 0;
	for(;;)
	{
		if(a->d[i] >= w)
		{
			a->d[i] -= w;
			break;
		}
		else
		{
			a->d[i] = (a->d[i] - w)&BN_MASK2;
			i++;
			w = 1;
		}
	}
	if((a->d[i] == 0) && (i == (a->top - 1)))
		{ a->top--; }
	return (1);
}

int BN_mul_word(BIGNUM *a, BN_ULONG w)
{
	BN_ULONG ll;

	w &= BN_MASK2;
	if(a->top)
	{
		if(w == 0)
			{ BN_zero(a); }
		else
		{
			ll = bn_mul_words(a->d, a->d, a->top, w);
			if(ll)
			{
				if(bn_wexpand(a, a->top + 1) == NULL) { return (0); }
				a->d[a->top++] = ll;
			}
		}
	}
	return (1);
}

#endif
